Solid Phase Micro Extraction (SPME) is a sampling method in which analytes of interest are absorbed into or adsorbed onto a coating deposited on a fiber. The fiber is then transferred to an injection port of a separating analytical instrument, such as a gas chromatography (GC) system, where desorption of the analytes from the fiber occurs. The analytes travel through a capillary column of the GC system, which separates the analytes based upon their respective retention times. The separated analytes can then be delivered from the GC system column to a detector, for example a mass spectrometry (MS) system, e.g., a mass spectrometer. The MS system ionizes the analytes, separates the resulting ions according to their mass-to-charge ratios, detects the ions, generates signals based upon the detected ions, and then processes the resulting detected ion signals into mass spectra, from which the analytes can be identified.
Although use of a system that incorporates both GC and MS provides good selectivity, the time taken to run the analytes through the GC column can be approximately five (5) to ten (10) minutes, given typical GC column retention times. Further, GC can limit the library of analytes which can be detected by MS. For example, a GC-MS system does not allow for analysis of non-volatile analytes that will not pass through the GC column.